1. Field of the Invention
This invention relates, generally, to tell-tales of the type used in sailboating. More particularly, it relates to a tell-tale that is visible at night.
2. Description of the Prior Art
Tell-tales are well-known devices used by sailors to determine prevailing wind conditions. Typically, they are formed of an elongate strip of lightweight, flexible material so that are easily displaced by wind. They are mounted at strategic places on a sailboat, such as the leading edge of a sail, so that they are easily visible; as they stream in the wind, they provide information about air flow over the sail, which is in most cases an air foil surface, so that the sail may be trimmed accordingly.
The primary shortcoming of the first tell-tales, and of most tell-tales currently in use, is that they are not visible under poor lighting conditions. Thus, where a race is being conducted that includes nighttime sailing, conventional tell-tales have little utility. Most sailors improvise a tell-tale illuminating means by directing a flashlight at the tell-tales time to time during the night, but this expedient provides only intermittent information unless the flashlight is used without interruption, and that, of course, is somewhat impractical.
Several inventors have provided other means for nighttime illumination of tell-tales. For example, Wheeler in U.S. Pat. No. 4,886,007 provides a small light source mounted near a tell-tale to illuminate it. Another illuminated wind indicator is disclosed in U.S. Pat. No. 4,481,505 to Thompson.
While the earlier means for illuminating tell-tales perform their intended function, they still include a few drawbacks. For example, when a light source that illuminates a tell-tale is mounted near the tell-tale, it provides a beam of light that illuminates the tell-tale when it is in or near a normal operating condition. When the tell-tale is displaced appreciably away from a normal operating position, it lies outside the fixed beam of light and is substantially invisible.
Another drawback of the known tell-tale lighting means is that the external lighting systems and their mounts are relatively bulky and expensive and often cease functioning because they are exposed to the elements.
An additional drawback of external lighting systems is they degrade night vision due to the excessive amount of light they produce, thereby lessening the Helmsman's ability to see wave patterns ahead and to windward.
Accordingly, there is a need for a tell-tale illumination means that illumines a tell-tale in all of its positions, and which does not require mounting means for holding external illumination devices. In view of the prior art considered as a whole at the time the present invention was made, however, it was not obvious to those of ordinary skill in this art how such means could be provided.